Apparatus for constructing a monolithic silo

ABSTRACT

System for constructing concrete silos wherein molds are sequentially erected and filled as a three tiered mold unit with a crane scaffold supported on the top mold by radial arms which rest on ledges extending inwardly from the inner face thereof. The outer form of the bottom mold is then dismantled into semicircular sections, raised by using the three jib cranes of the crane scaffold and erected as the fourth tier. The inner form of the bottom mold is then dismantled in predetermined length sections for passage through the restricted space between the crane scaffold and the third tier and then erected to complete the fourth tier mold. The crane scaffold is then elevated by suspending it from the top of the fourth tier; the radial arms are then seated on the horizontal ledges of the fourth tier. A cart is rotatably mounted about the center post of the scaffold for evenly feeding concrete into the molds. Safety means are provided.

Umted States Patent 1191 1111 3,7765% Weaver m. 4, 1973 APPARATUS FOR CONSTRUCTING A MONOLITHIC SILO A Primary ExaminerJ. Spencer Overholser Assistant Examiner-Ben D. Tobor [76] Inventor. Richard L. Weaver, Myerstown, Pa. Atwmey Henry N Paul Jr. et al- [22] Filed: July 6, 1971 21 Appl. No.: 159,948 57 ABSTRACT Related US. Application Data Division of Ser. No. 720,687, April 11, 1968, Pat. No. 3,619,431.

System for constructing concrete silos wherein molds are sequentially erected and filled as a three tiered mold unit with a crane scaffold supported on the top mold by radial arms which rest on ledges extending inwardly from the inner face thereof. The outer form of the bottom mold is then dismantled into semicircular sections, raised by using the three jib cranes of the crane scaffold and erected as the fourth tier. The inner form of the bottom mold is then dismantled in predetermined length sections for passage through the restricted space between the crane scaffold and [56] References Cited the third tier and then erected to complete the fourth UNITED STATES PATENTS tier mold. The crane scaffold is then elevated by suspending it from the top of the fourth tier; the radial 3: 2 arms are then seated on the horizontal ledges of the 9/1906 249/45 fourth tier. A cart is rotatably mounted about the cen- 45 090 5 92 5 1 425/64 ter post of the scaffold for evenly feeding concrete 1,163,798 12/1915 Willi 425 4 into the molds. Safety means are provided. 1,122,329 12/1914 Stoeser 249/144 908,326 12/1908 Polk 425/64 2 Claims, 24 Drawmg Figures 1? 24 I06 l3 H |07 I06 14 -y Q 1 l I i. LLLijl s 11 fijwlr g PATENTEDUEB 4W5 SHEET 1 [IF 8 INVENTOR RICHARD L. WEAVER ATTORNEY I PATENTEUUEB 41915 3,776,502

INVENTOR RICHARD L. WEAVER BY v ATTORNEYS PATENTEU U59 4 3 SHEEI 3 IF 8 RICHARD L. WEAVER ATTORNEYS PATENTED DEC 4 I973 sum w 0F 3 T0 OPERATOR 0 R M MD SM E I WU CI UA OS I ENTOR RICHARD L. WEAVER /M fi /M ATTORNEYS PATENTED 7 3.776. 502

sum. 5 ur a RICHARD L. WEAVER BY WWQ Vim/L ATTORNEYS PATENTED 41975 v 3,776,502

' 'SHEE1'70F3 EK I02 I INVENTOR RICHARD L. WEAVER W WM ATTORNEYS PATENTED DEB 41973 SHEET 8 OF 8 INVENTOR RICHARD L. WEAVER ATTORNEY-S APPARATUS FOR CONSTRUCTING A MONOLITHIC SILO CROSS REFERENCE TO RELATED APPLICATIONS This application is a division of application Ser. No. 720,687 filed Apr. 11, 1968, now US. Pat. No. 3,619,431.

This invention relates to a system for constructing monolithic silos or other concrete structures having annular walls. While systems involving movable forms are well known, the large silos being constructed today have presented problems which are quite different from those faced when the prior systems were developed.

A system today must meet labor and material requirements. For example, it is no longer practical to mix concrete at the site; the concrete must be purchased in about sixcubic yard batches. This material should be poured as quickly as possible to product the best possible wall. Efficient and expeditious pouring also reduces the cost of concrete. The system must be designed to accept qualified personnel with a minimum of training and with a high degree of safety. The apparatus must be well engineered and designed to minimize the labor required and the chance of possible error in operation.

This invention provides a system suitable for erecting silos of diameters up to 24 feet and more, the silos rising to a height of 60 to 70 feet or more. The system is designed for two or three operators. The system accepts standard ready-mix concrete truck batches in the amount of 6 yards or more.

A ring mold about 4 feet high and of the desired silo diameter is erected on a base and filled. Two more molds are then similarly erected and filled to form a three tiered mold unit. During this process a crane scaffold is erected within the molds and, when desired, supported preferably by nine equiangular radial arms on horizontal ledges on the inner face of a mold. When the crane scaffold is mounted on the top mold, it is about 12 feet above the base and is supported solely by the inner forms of the molds. Preferably, the inner form of each mold is designed to produce protrusions or mounds on the inner wall of the silo which serve to support the rather considerable weight of the scaffold and operators. The operators and scaffold used for erecting a 24 foot diameter silo weigh about 4,000 pounds.

The system is designed to enable the dismantling of the bottom mold after the other two upper molds have been erected and filled. Usually, with optimum concrete handling, a mold can be filled in the morning and dismantled in the afternoon. The bottom outer form is moved first and then the bottom inner mold is moved in predetermined length sections.

Since the top mold usually contains concrete which has not hardened or set to any significant degree when the bottom mold is transferred, the cranescaffold is supported substantially entirely by the middle mold inner form. The importance of sound supporting engagement of the middle inner form with the silo inner wall will therefore be appreciated.

After the transferred mold has been assembled, the crane scaffold is raised by three jib cranes on the scaffold which are sequentially operated to lift the scaffold incrementally through the 4 feet to the upper portion of the newly erected inner form. The jib cranes support the weight of the crane scaffold during this lifting step on the top edge of the newly erected inner form.

The radial arms of the scaffold have feet which automatically move into seating engagement with the ledges when the scaffold is raised. These feet are operatively connected to safety means arranged to support the scaffold on the inner form if a radial arm or jib crane should fail.

These and further objects and advantages of the present invention will become more apparent upon reference to the following specification, appended claims and drawings wherein:

FIG. 1 is a top plan view of the system showing the basic structure;

FIG. 2 is a side view taken on line 22 of FIG. 1 showing the crane scaffold supported on a ledge of a top mold;

FIG. 3 is a top plan view on reduced scale showing a semi-circular portion of the outer form of the bottom mold of the three tiered mold unit, being lifted by the jib cranes;

FIG. 4 is a side view showing the outer form portion during lifting with the outer form shown in phantom lines in its final raised position;

FIG. 5 shows the concrete reinforcing means which is then fabricated for the concentric wall;

'FIG. 6 is a side view showing a section of the bottom inner form in condition for dismantling by use of a trolley and raising by a jib crane through the space between the crane scaffold and the top inner form as shown in phantom lines;

FIG. 7 is a detail of the trolley wheels on the ring track;

FIG. 8 is a side view showing the initial incremental raising movement of the crane scaffold by the jib cranes;

FIG. 9 is a side view showing the concrete pouring step;

FIG. 10 is a perspective view showing the saddle used when lifting the scaffold;

FIG. 11 is a perspective view of the form engaging means, a foot being shown which seats on a ledge of the inner form;

FIG. 12 is a side view taken on line 12-12 of FIG. 8;

FIG. 13 is a view taken on line 13-13 of FIG. 2;

FIG. 14 is a view taken on line 14-14 of FIG. 2 showing, as does FIG. 13, details of the floor support;

FIG. 15 is a perspective view of an inner form section;

FIG. 16 is an enlarged view showing the connection means for the inner form sections;

FIG. 17 is a vertical cross-sectional view of the inner form section with phantom lines showing the bulging distortion produced by the concrete;

FIG. 18 is a perspective view of an outer form section;

FIG. 19 is an enlarged view showing the connection means for the outer form sections;

FIG. 20 is a vertical section of the outer form section;

FIG. 21 shows the cart;

FIG. 22 is a side view in section showing a safety cage and net;

FIG. 23 is a perspective view of the ladder, and

FIG. 24 is a perspective view of a modified section for the inner mold.

FIGS. 1 and 2 show the system following the pouring of concrete into the top mold of a previously erected vertical stack of similar ring molds, concrete reinforcement rod 16 extending upwardly from the top of the poured annular concrete wall 17. The system shown uses nine radial arms 22 and this is satisfactory for a silo of about 20 feet in diameter. For silos 16 feet in diameter, seven radial arms are used; and for silos 24 feet in diameter, radial arms are used.

Preferably the system includes a three tiered mold unit M and a crane scaffold S, the crane scaffold including:

a center post 21;

radial arms 22, nine such arms being shown radiating as spokes from the center post 21 and each including a radial truss 23, a form engaging means or foot 24, and a depending support arm 25 for the trolley monorail 26;

an annular dock 29 made up of substantially trapezoidal deck segments 30 connected to the radial arms 22;

three jib cranes 27 rotatably mounted on the center post 21;

a hydraulically powered concrete cart 28 rotatably mounted on the center post 21;

a frame 31 which can be seated on the top mold and having a brace 32 extending to the center post 21, this frame 31 being used when concrete is raised from ground level up the outside of the silo;

a hydraulic power unit 33 mounted on the radial arms 22 near the center post 21 for supplying hydraulic power through lines not shown to each jib crane 27 and the hydraulically driven concrete cart 28, the power unit 33 including an electric motor, pump, and oil reservoir thereby requiring only an electrical cable connection to a power source on the ground.

The system as shown in FIGS. 1-4 is in condition for the raising of the bottom mold. By hanging a ladder over the outside of the mold unit M, an operator can climb down to the bottom outer form 34 and divide it into semi-circular portions 35 and 36 as seen in FIG. 3, one of the semi-circular portions 35 being shown in FIG. 4 while being lifted to a top position (shown in phantom lines) by the three jib cranes 27.

When the outer semi-circular portion 36 of the outer form 34 has been raised and connected to portion 35 as well as the subjacent outer form 37, an annular concrete reinforcing means 38 is erected on the reinforcement rods 16, as seen in FIG. 5.

The next step is the transfer of the bottom inner form 40. FIGS. 6 and 7 show the trolley 41 in position for enabling an operator to progressively dismantle the bottom form 40 into arcuate sections 42 (FIG. of predetermined length which are lifted by a single jib crane 27 upwardly through the rather restricted space between the top tier inner form 43 and the floor segment 30. The passage of a section 42 through a restricted space is shown in phantom lines in FIG. 6.

The sections 42 are then assembled as a rigid inner form 40 on top of the inner form 43 and the thus formed new top mold is now ready to receive concrete.

Prior to the concrete pouring step, however, the crane scaffold S is lifted from a seated position on inner form 43 (FIG. 2) to a seated position on the newly formed top inner form 40. FIG. 8 shows jib crane 27 lifting the crane scaffold S with the entire weight of the crane scaffold being supported by the inner forms 40,43 and 45 through the pulley saddle 50. Preferably, the hydraulic power unit 33 is designed with a capacity to operate only one single jib crane at a time, thereby reducing the weight of this unit. Each of the three cranes is therefore separately and sequentially operated to incrementally lift the crane scaffold S through the distance of four feet to the new seated position on inner form 40.

FIG. 9 shows the concrete pouring step whereby a concrete bucket 46 of about 400 pounds capacity is hoisted by a ground based power unit (not shown) into dumping relationship with cart 28. When filled, the cart 28 is hydraulically driven by power unit 47 around the deck 29 to fill the top mold of mold unit M as quickly and evenly as possible.

The cycle is then repeated until the desired silo height has been reached at which time provision is made in the top mold for forming roof beam slots or notches in the top of the concrete wall. The outer forms are lowered to the ground in semi-circular portions 35 and 36. Support of the crane scaffold S is transferred to the top of the silo wall and the inner form sections 42 are dismantled, raised and then lowered outside the silo wall. The crane scaffold S is then lowered inside the silo and dismantled into parts which are of such size that they pass through normal silo bottom access openmgs.

Preferably, metal ladder rungs are cast in place in the outside wall during the wall formation. Also a vertical access passage of bay wall may be provided by utilizing, as seen in FIG. 1, outer form sections 48 of the desired shape and core member 49 which coacts with an inner form section 42 to define the substantially semi-circular bay wall 110 protruding outwardly from the main annular wall 17.

The apparatus for erecting an annular wall 17 for a silo or the like will therefore be understood as including a vertical stack of ring molds M wherein the inner form 40 of each mold has an inwardly extending ledge means or ledges 60 about We inches wide for supporting the crane scaffold S. The crane means 27 in the form of three jib cranes 27 enables the raising of the bottom outer form 34 to a top seated position on the remaining outer forms as well as a similar raising operation for the inner form 40. Means, such as the pulley saddle 50, are provided for supporting the crane scaffold S through the crane means 27 on the newly erected top inner form 40. In the lower part of the silo the bay wall 110 is usually omitted; an outer form about 42 inches in horizontal arcuate length is substituted therefor.

Preferably the inner forms 40 include molding means for forming protuberances or mounds on the inner surface of the silo wall for interlocking support of the inner form. In the modification shown in FIGS. 1517, the molding means is provided by a reinforcing frame 61 on the inner form which defines a plurality of main plate portions 62 which are distorted, that is, flexed within their elastic limit, by the weight of the concrete poured in the mold (about 400 pounds) to define mounds 63 (FIGS. 2 and 17) on the wall for interlocking support of the inner forms 40. The combination of the reinforcing frame 61 and main plate portions 62 is variable to enable the production of mounds of the desired pattern and size. Mounds having a surface area of 18 square inches and which extend inwardly about A to 1 inch have been found to be satisfactory.

When the concrete is poured, the outer form is placed under tension and very little distortion of the outer form takes place. The inner form, however, is placed under severe compression and this phenomenon is utilized for distortion of main plate portions 62 for supporting the apparatus. Because the reinforcing frame 61 of the inner form 40 includes abutting side flanges, spacing connector means 65, such as the three connector means 65 shown at the left portion of FIG. 15, are utilized at a vertical joint between inner sections 42. These spacing connector means 65 can be knocked out of place after removal of locking pin 66 and thereby free an inner form section 42 for dismantling.

As seen in FIG. 2, the foot 24 of radial arm 22 is seated on ledge 60 and presses against the inner section of form 42 to produce a wedged seating of the foot. In this fashion the inner form is reinforced and the scaffold S is firmly seated thereon. Preferably the foot 24 is pivotally mounted on a rod 66, as seen in FIGS. 11 and 12, which is telescopically received and locked by pin 67 within the radial truss 23 to enable a radial adjustment of about 6 inches to insure a wedged seating action.

A safety means 70 is provided in the form of an outwardly and downwardly extending safety bar 70 positioned for engagement with the bottom seating flange 71 of the inner form. As seen in FIG. 2, this bar 70 assumes a position just above the seating flange 71.

Each jib crane 27, as seen in FIG. 8,.includes a main member 73 and an upper stay element 74 rotatably mounted on center post 21. A hydraulic hoist 75 is mounted on the outer portion of the main member 73 and a jack leg 76 is pivoted to the hoist 75 for seating engagement with a lug 77 (FIG. 11) on a radial truss 23 when the scaffold is being lifted.

Referring now to details of the ring molds, FIGS. -20 show each inner mold section 42 as including a main plate 81 having a smooth mold face 82 and vertical side flanges 83 for abutting connection by lugs 84 which pass through flange holes 85 and are locked in place by wedge pins 86. Chains 87 connect all connecting means to the sections.

Inner section 42 of FIG. 15 shows the reinforcing frame 61 as including side flanges 83 and full length top and bottom seating flanges 71, top and bottom bands 88, four equally spaced intermediate U-channels 89, and three equally spaced intermediate vertical members 90. The reinforcing frame defines distortable main plate portions 62. The ledge means 60 is formed by ledge 60 extending horizontally from an upper corner of section 42 with a vertical bar 91 extending to the top flange 71 to define a housing for a foot 24. FIG. 16 shows finger 92 clamping horizontal flanges 71 together with a keeper pin 93 holding the finger in place.

The outer mold section 80 is slightly larger than the inner mold section 42 and includes (FIGS. 1820) a main plate 95, vertical side flanges 96 with similar connecting means 97, horizontal top, intermediate, and bottom bands 98, and horizontal seating flange elements 99 at each corner which extend a short distance of up to a foot or more from the side flanges 96.

The horizontal edges of the outer sections 80 are connected by bottom L-bars 100 which pivot to a position inside of and under top horizontal latches 101. The horizontal portions 102 of the L-bars can support a lower outer section; this is important when the bottom outer form is divided into semi-circular portions as seen in FIG. 3. To prevent sidewise disengagement the lefthand latch 101 in FIG. 18 opens to the right to accept a clockwise pivoting L-bar 100'.

Referring now to FIG. 8, it will be seen that the foot 24 is biased into seated position by tension spring 105. While a separate spring could be used, spring 105 is connected also to safety bar for urging the bar into engagement with the inner form 43 just above the bottom flange 71.

The deck segments 30 seat in troughs 106 on the radial trusses 23 as seen in FIGS. 13 and 14. A locking device 107 shown in FIG. 13 positioned inwardly of outer trough 106 prevents the outermost deck segment 30 from tilting.

The trolley monorail 26 is supported by support arm 25 and also by hangers 108 seated on and depending from the deck 29 as seen in FIG. 4. This arrangement also serves to maintain the deck segments 30 in the troughs 106.

Preferably the concrete is pumped upwardly by pump 199 (FIG. 6) through a flexible conduit 200 and through the internal bore of the center post 21 (about 3 /2 inches in diameter) from which it is directed into a flexible discharge piep 201. This concrete delivery system would replace the cart system previously discussed. The pump 199 could be located at ground level.

Preferably each arcuate section of the inner form has a ledge 60 which includes an outwardly projecting portion for engagement by the lifting cable 202 with cable hook 203 connected to the angle brace 205 (FIG. 5 As will be seen in the dotted line showing of FIG. 6, the balance of the section is such that it always tends to pivot the bottom surface of the cable engaging ledge 60 into engagement with the cable 202. In use, the cable 202 is placed under the ledge 60 as shown in FIG. 15, and the hook 203 connected, following which the section is moved inwardly and then allowed to swing by gravity into the position shown in dotted lines in FIG. 6, for passage upwardly between the scaffold and the lower inner form. Proper dimensional relationships can be established whereby very little guidance by the operator is required.

Various safety devices can be employed, and it is preferred that an outer safety cage 210 as shown in FIGS. 22 and 23 be used. The cage 210 hooks over the top of the forms with the safety chain 211 coupled to the inner form or the scaffold. The safety cage, preferably, is about 16 feet long with suitable protective caging in arcuate form and a solid bottom member. Internally, safety devices are provided, and, as seen in FIG. 22, a full circular net 212 is provided below the trolley 41. The net 212 is mounted on an annular, rigid expander ring 214 which is suspended from the crane scaffold by suspension wires 215. The center portion of the net 212 is connected to the bottom'of the center post 21. Further, it is sometimes preferable for the operators to vacate the platform while it is raised, and to accommodate this, a control rope 216 (FIG. 8) is provided for the valve control of the hydraulic hoist on each jib crane, this control rope passing over the pulley 217 outwardly to the forms on which the operators will support themselves during scaffold elevation. The previously discussed cage 210 may also be used for the operators during this elevation.

This system of silo construction enables the production of a cylindrical silo having accurate predetermined dimensions, this being particularly important when bottom unloaders of the radial sweeping auger type are employed. The spokes of the scaffold press the inner forms outwardly and maintain the desired dimension.

Preferably, on the inner forms the braces 89 are U- channels this being particularly important on large diameter silos such as 24 feet. When U-channels are employed, the vertical elements 90 can be eliminated.

FIG. 24 shows a modified inner form section involving two sheet metal plates 220-221 welded together with swinging levers 223 and 224 connected at the welded joint. A cable 225 is then hooked to side chains 226 which are welded to the plates and the lever 223 is then swung out to produce the desired curvature. By changing the connection with the chains, various curvatures can be produced.

While the invention has been described with reference to certain embodiments, they are to be considered illustrative rather than limiting, and it is intended to cover all further embodiments that fall within the spirit and scope of the appended claims.

What is claimed is:

1. In a mold for concrete or the like, wherein inner and outer mold forms are used to receive concrete therebetween and wherein one of the mold forms comprises a plurality of sections disposed in end-to-end engagement along at least one parting line, a mold section including molding means for forming protuberances on a concrete wall formed thereby for vertical support thereon, said molding means including a main plate having a smooth mold face, and with said mold section including a reinforcing frame fixedly connected to an opposite face of said plate defining a plurality of main plate portions and which comprise means responsive to the weight of concrete disposed between inner and outer mold forms when used in forming a wall, for laterally distorting under the weight of concrete in a wall being formed an amount for defining with said plate portions, laterally protruding mounds on a concrete wall formed thereby for vertical support thereon.

2. The apparatus of claim 1, including a plurality of said sections in the combination and including means for connecting said sections together in tight end-toend abutment.

Patent No. 3,775,5 2 Dated December 4, 1973 "Inventor(s) Ri hard L. Weaver It is certified that error appears in the ahoveidentified patent i and that said Letters Patent are hereby corrected as shown below:

Column 1, line 20, change f'pr'coduct" to produce--.

Column 2, line 45, delete the word "side".

Signed and sealed this 30th day of April 19%.

(SEAL) Attest:

EDWARD ILFLETClL-JR R. c. MARSHALL DANA-I Attesting' Offioer' Commissionerof Patents 

1. In a mold for concrete or the like, wherein inner and outer mold forms are used to receive concrete therebetween and wherein one of the mold forms comprises a plurality of sections disposed in end-to-end engagement along at least one parting line, a mold section including molding means for forming protuberances on a concrete wall formed thereby for vertical support thereon, said molding means including a main plate having a smooth mold face, and with said mold section including a reinforcing frame fixedly connected to an opposite face of said plate defining a plurality of main plate portions and which comprise means responsive to the weight of concrete disposed between inner and outer mold forms when used in forming a wall, for laterally distorting under the weight of concrete in a wall being formed an amount for defining with said plate portions, laterally protruding mounds on a concrete wall formed thereby for vertical support thereon.
 2. The apparatus of claim 1, including a plurality of said sections in the combination and including means for connecting said sections together in tight end-to-end abutment. 